Preparing snow surface for skiing and other snow sports



Feb-24, 1970 o. H. WALLI NGFORD 3,496,343

PREPARING SNOW SURFACE FOR SKIING AND OTHER SNOW SPORTS Filed April 29, 1968 2 Sheets-Sheet 1 INVENTOR OTTO H. WALLI-NGFORD ATTORNEYS Feh, 24, 1970 o. H. WALLINGFQRD 3,496,843

PREPARING SNOW SURFACE FOR SKIING AND OTHER SNOW SPORTS Filed April 29, 1968 2 Sheets-Sheet 2 x 4/ I I 3 4/ 1 F i6. 3A 46-5 INVENTOR OTTO H, WALLINGFORD ATTORNEYS United States Patent O 3,496,843 PREPARING SNOW SURFACE FOR SKIING AND OTHER SNOW SPORTS Otto H. Wallingford, Auburn, Maine, assignor to Valley Engineering, Inc., Auburn, Maine, a corporation of Maine Filed Apr. 29, 1968, Ser. No. 725,060 Int. Cl. E01c 19/28 US. C]. 9422 11 Claims ABSTRACT OF THE DISCLOSURE Method and apparatus for conditioning a snow-covered surface by the employment of one or more rolls, each having a foraminous envelope that is sharply apertured The rolls are drawn across the surface in a direction which forms an oblique angle relative to the axis of rotation of any roll.

In the disclosed embodiment, two foraminous drums are hinged together and disposed with equal leading and trailing angles relative to the axis of draw. Each drum i of expanded metal, forming strips which provide a multiplicity of scraping edges over the associated envelope.

By being drawn at an angle, the drums tend to shear and scrape the snow-covered surface. Since the drums rotate and are apertured, they sift the scraped particles of snow and deposit a powdery layer that is suitable for skiing.

BACKGROUND OF THE INVENTION This invention relates to the conditioning of snowcovered surfaces, and, more particularly, to the rendering of such surfaces more suitable for skiing and winter sports.

In the case of many winter sports, such as skiing, it is desirable for the surface cover to be in a form known as powder. This is the condition that commonly prevails after an ordinary snow fall.

However, after the surface has been subjected to extensive use, the powdery cover becomes compacted and less suitable. A further adverse effect is the glazing of the surface that often accompanies variations in temperature.

In an attempt to maintain a snow-covered sporting surface in suitable condition, in the absence of the assistance from Mother Nature, it is common practice to use Snowmaking machinery. In addition, other machinery is used to smooth the snow in order to eliminate ruts and cover barespots. Snowmaking machinery is not only costly to acquire and often difficult to use, it operates over a restricted temperature range. The machinery used to smooth the snow does not provide the desired powder cover and is unsatisfactory where glazing has occurred.

Accordingly, it is an object of the invention to expedite the conditioning of snow-covered surfaces. A related object is to render snow-covered surfaces more suitable for skiing.

A further object of the invention is to compensate for the compacting of a snow-covered surface as a result of extensive use. A related object is to compensate for compacting as a result of extensive skiing.

Still another object of the invention is to treat a snowcovered surface which has become glazed. An associated object is to render a glazed surface more suitable for skiing.

Another object of the invention is to achieve the suitable conditioning of snow-covered surfaces without the need for equipment that is of limited effectiveness, limited operating range and often requires special training for use.

SUMMARY OF THE INVENTION In accomplishing the foregoing and related objects the invention provides for scraping a snow-covered surface to produce particles which are sifted and deposited to form a powdery layer that is suitable for winter sports such as skiing.

To both scrape the snow-covered surface and deposit the scraped particles, an apertured roll is employed that is drawn over the surface in a direction which forms an oblique angle relative to the rotational axis of the roll. Consequently, the thrust which draws the roll resolves itself into two components, one component along the axis of rotation to drag the roll and the other component tangential to the axis of rotation to bring about rotation. The axial component of thrust roduces a scraping effect, while the rotation draws the scraped particles up into the roll where they are sifted and deposited as the desired powder cover.

In accordance with one aspect of the invention, the mechanism used to provide the proper orientation of the apertured roll with respect to the axis of draw is in the form of an adjustable connector which extends to a hitch for a prime mover.

In accordance with a further aspect of the invention the roll is accompanied by a second roll of similar construction and disposed to have a trailing oblique angle of the same magnitude as the leading oblique angle of the first roll. This is illustratively achieved by hinging one end of a roll support mechanism for the first roll to a corresponding mechanism for the second roll and interconnecting the opposite ends of the support mechanisms by an adjustable link.

In accordance with a still further aspect of the invention each apertured roll is formed by an expanded metal drum with a plurality of scraping edges.

BRIEF DESCRIPTION OF THE DRAWINGS Other aspects of the invention will become apparent after considering several illustrative embodiments taken in conjunction with the drawings in which:

FIGURE 1 is a perspective view of a surface conditioning machine in accordance with the invention;

FIGURE 2 is a plan view of the machine shown in FIGURE 1;

FIGURES 3A thru 3B are views illustrating details of adjustable connectors for the machine of FIGURES 1 and 2; and

FIGURE 4 is a partial perspective view of an expanded metal drum for the machine of FIGURES 1 and 2.

DETAILED DESCRIPTION OF AN ILLUSTRATIVE EMBODIMENT Turning to the drawings, FIGURE 1 shows a machine 10 for conditioning a snow-covered surface in accordance with the invention. The machine 10 is illustratively eonstituted of two foraminous rolls or drums and 30' which are apertured and desirably have a multiplicity of scrapping edges as discussed in detail below. The rolls 30 and 30 are rotatably mounted in standard fashion in respective frames and 40'. The frames, and hence the rolls, are disposed at pre-assigned angles with respect to an axis of draw D for the machine 10.

To obtain the desired angular orientation for the forward roll 30, the frame 40 is pivotally attached to two draw bars 42 and 44 of unequal length. One of the bars, for example the bar 42, is adjustable to permit variations in the angle of draw. The forward ends of the draw bars 42 and 44 meet at a loop 45. The latter permits connection of the machine 10 to a prime mover, such as a selfpropelled vehicle 47, using a hitch of conventional design.

For the rearward roll, the desired angular orientation is illustratively obtained by hinging its frame 40' to the forward frame 40 and by having the opposite ends of the frames interconnected by an adjustable link 46.

Since the two rolls 30 and 30 are at an angle to the axis of draw D, forward motion of the prime mover 47 causes the rolls 30 and 30 to scrape the snow covered surface 20 and simultaneously sift the scraped particles up into the rolls, resulting in the deposit of a powdery snow layer that is desirable for winter sports such as skiing.

Although two rolls 30 and 30' of conditioning machine 10 in FIGURE 1 are shown with hinged frames 40 and 40', it will be appreciated that one or more rolls, and other angular dispositions, may be employed.

Details of a representative disposition of the rolls 30 and 30' with respect to the axis of draw D are illustrated in the plan view of FIGURE 2. The adjustable draw bar 42 is set so that the axis of rotation R of the forward roll 30 forms an acute leading angle 4: relative to the axis of draw D. Correspondingly, the adjustable frame link 46 is set so that the axis of rotation R of the rearward roll 30' forms an acute trailing angle relative to the axis of draw D. The leading and trailing angles 11 and are of equal magnitude, and the leading angle of the rearward roll is the supplement of its trailing angle i.e., the magnitude in degrees of the leading angle 0' is ISO- t.

Although the rolls 30 and 30' may be disposed angularly in a variety of ways, the symmetric configuration of FIG. 2 achieves balanced operation. As the conditioning machine is moved forwardly in the direction indicated by the arrow, thrusts are applied to the rolls 30 and 30', as represented by the vectors a and a in the vector diagrams associated with FIG. 2.

The thrust vector a for the forward roll 30 resolves itself into two component vectors b and c, which are respectively axial and tangential for the roll 30. The tangential vector c tends to produce rotation and move the roll 30 away from the axis of draw D. This effect is counterbalanced by the axial drag of the axial vector b.

correspondingly, for the rearward roll 30, a tangential vector 0' produces rotation that is counterbalanced by an axial vector b.

The net effect of the axial forces b and b is to produce scraping, while the tangential forces 0 and c produce rotation and sifting of the scraped particles. Further, since the corresponding vectors shown in FIG. 2 are of equal magnitude, the machine 10 tends to follow the axis of draw D without sideways deviations.

However, it has been found in practice that when the leading and trailing angles b and are unequal in magnitude, imbalance effects are introduced which result in a pull from side to side during operation of the machine 10.

The magnitudes of the angles and depend upon the extent to which the snow-covered surface (FIG. 1) has become compacted or glazed. Under severe conditions the angles 1: and 5' are desirably less than 45 in order to produce appreciable axial thrusts b and b. For moderate glazing and compacting of the surface 20 the angles 5 and are greater than 45 and less than 90. When the angles and become 90 there is no scraping effect at all.

Details of a suitable link 46 for adjusting the leading and trailing angles and 5 relative to each other are shown in FIGS. 3A and 3B. The link 46 is pivotally held by pins 41 and 41 in connectors 42 and 42' that are welded to the respective frames 40 and 40'. Forming the link 46 is a box member 46-1 which telescopically receives a channel member 46-2. The box member 46-1 is provided with a series of holes 46-a and the channel has corresponding registration holes 46-b. A removable pin 46c holds the box and channel members together at the desired distance of separation of the frames 40 and 40',

as shown by the cross-sectional view of FIG. 3B. The removable pin 46c is held in place by a cotter pin 46-d.

The adjustable draw bar 42 may be patterned after the adjustable link 46 of FIGS. 3A and 3B. Alternatively the bar 42 can be formed by a rod which is telescopically received by a pipe and held in position by a pin passing through holes of the pipe and the rod.

Considering the structural details for the rolls 30 and 30', each is advantageously formed by a drum of expanded metal, as shown by the partial perspective view of FIG. 4 for the forward roll 30*.

Such a drum is fabricated by slitting a piece of sheet steel and drawing the ends apart so as to form metallic strips in an elongated hexagonal pattern with outer edges 31 that are capable of scraping the surface to be conditioned. The apertures that are incident to the hexagonal strip pattern are appropriate for sifting the particles of snow that are scraped by the edges. The roll 30 is supported internally by spoked rims, e.g., the rim 32 of FIG. 4, whose hubs are attached to the shaft 33 on the axis of roll rotation.

Other varieties of expanded metal drum may be used to condition a surface in accordance with the invention; such as those disclosed by F. L. Shidler et al. in US. Patent 1,626,879 which issued May 3, 1927; J. F. MacDonald in U.S. Patent 2,730,054 which issued Jan. 10, 1956; J. R. Gruher in US. Patent 2,965,053 which issued Dec. 20, 1960; E. S. Grandrud in US. Patent 3,220,369 which issued Nov. 30, 1965; and P. Phan-Quang in US. Patent 1,839,000 which issued Dec. 29, 1931.

While various aspects of the invention have been set forth by the drawings, it is to be understood that the foregoing detailed description is for illustration only and that various changes in shape, proportion, arrangement of parts, as well as the substitution of equivalent elements for those shown and described, may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

I claim:

1. The method of preparing a snow surface for skiing and other snow sports which comprises the step of drawing a rotatable roll having a surface formed by an open network of strips of rigid material over a snow surface in a direction forming an oblique angle relative to the axis of rotation of said roll, whereby the edges around the openings of the network scrape the snow surface to produce particles of snow, scraped particles of snow are passed into the roll through openings of said network, and said particles of snow are then passed outwardly through openings of said network and deposited from the roll upon the scraped snow surface.

2. The method of preparing a snow surface for skiing and other snow sports which comprises the step of simultaneously drawing at least two rotatable rolls each having surfaces formed by an open network of strips of rigid material over a snow surface in a direction forming oblique angles relative to the axes of rotation of said rolls, the second roll being located behind the first roll in the direction of draw with its axis of rotation diverging from the axis of rotation of the first roll when viewed from the top, whereby the edges around the openings of said network successively scrape the snow surface to produce particles of snow, scraped particles of snow are passed into the rolls through openings of said network, and said particles of snow are then passed outwardly through openings of said network and deposited from the first and second rolls upon the scraped snow surface.

3. An apparatus for preparing a snow surface for skiing and other snow sports which comprises a roll which comprises a surface formed by an open network of strips of rigid material, and

means for rotatably mounting said roll with its axis at an oblique angle to the direction of draw,

whereby when the apparatus is moved in the direction of draw the roll is rotated upon said snow surface, the edges around the openings of said network scrape particles of snow therefrom, scraped particles of snow are passed into the roll through openings of said network and then passed outwardly through openings of said network and deposited upon the scraped snow surface.

4. An apparatus as defined in claim 3 wherein said mounting means comprises means for adjusting the magnitude of the oblique angle between the axis of the roll and the direction of draw.

5. An apparatus as defined in claim 3 wherein said mounting means comprises a frame, a first draw bar connected to one end of said frame and a second, adjustable draw bar connecting the other end of said frame with said first draw bar at a tow point.

6. An apparatus as defined in claim 3 wherein the surface of the roll is formed of expanded metal having metallic strips arranged in an elongated hexagonal pattern.

7. An apparatus for preparing a snow surface for skiing and other snow sports which comprises a first roll which comprises a surface formed by an open network of strips of rigid material,

means for rotatably mounting said first roll with its axis at an oblique angle to the direction of draw, a second roll which comprises a surface formed by an open network of strands of rigid material, and

means for rotatably mounting said second roll behind said first roll in the direction of draw, with its axis at an oblique angle to the direction of draw and diverging from the axis of rotation of the first roll when viewed from the top,

whereby when the apparatus is moved in the direction of draw the rolls are rotated upon said snow surface, the edges around the openings of said network successively scrape particles of snow therefrom, scraped particles of snow are passed into the rolls through openings of said network and then passed outwardly through openings of said network and deposited upon the scraped snow surface from the first and second rolls successively.

8. An apparatus as defined in claim 7 wherein said mounting means comprises means for adjusting the magnitude of the oblique angle between the axis of the first roll and the direction of draw and means for adjusting the magnitude of the oblique angle between the axis of the second roll and the direction of draw.

9. An apparatus as defined in claim 7 wherein said mounting means for the first roll comprises a frame, a first draw bar connected to one end of said frame and a second, adjustable draw bar connecting the other end of said frame with said first draw bar at a tow point.

10. An apparatus as defined in claim 7 wherein the surface of each roll is formed of expanded metal having metallic strips arranged in an elongated hexagonal pattern.

11. An apparatus as defined in claim 7 wherein said means for rotatably mounting said first roll comprises a first frame and said means for rotatably mounting said second roll comprises a second frame having one end hinged to one end of said first frame and its other end connected to the other end of said first frame by an adjustable link.

References Cited UNITED STATES PATENTS 639,829 12/1899 Schaffer 94-50 1,211,811 1/1917 Bailey 94-50 XR 1,724,363 8/1929 Reed 172-537 XR 1,830,218 11/1931 Barker 172-596 1,839,000 12/1931 Phan-Quang 94-50 XR 1,895,831 1/1933 West 172-597 2,151,918 3/1939 Ingram 172-596 3,033,295 5/1962 Brundage l72597 3,119,314 1/1964 Schiel 94-50 3,220,369 11/1965 Gandrud 94-50 XR OTHER REFERENCES The Navy Civil Engineer, pp. 24, 25, April 1960.

JACOB L. NACKENOFF, Primary Examiner US. Cl. X.R. 94-50 

